A while back, I posted about creating a Forth-inspired programming language that uses emoji as words (functions) and said that I would post the source code. I keep my word—this weekend I cleaned up the code and published it.

I've built a tool that transpiles emoji source code into either Crystal or Python, and then builds and runs the transpiled source.

Here's the solution to Project Euler Problem 1, with comments so that you can more easily follow the flow:

💭 Project Euler Problem 1:
💭 Find the sum of all the multiples of 3 or 5 below 1000 => 233168

💭 Define a word to check if a number is divisible by 3 or 5
📖❓                    💭 Stack: ( n -- bool )
  📚                    💭 Duplicate n for two tests
  🔢3 🔀 🔢0 🟰          💭 (n%3==0)
  🔄
  🔢5 🔀 🔢0 🟰          💭 (n%5==0)
  ⚡                    💭 (n%3==0 OR n%5==0)
📕

💭 Declare variables
📦 💯                   💭 sum variable
📦 🧮                   💭 counter variable

💭 Initialize variables
🔢0 💾 💯               💭 sum = 0
🔢1 💾 🧮               💭 counter = 1

💭 Loop from 1 to 999 (inclusive)
🔁
  💭 Get counter and check if divisible by 3 or 5
  📤 🧮                 💭 counter
  📚 ❓                 💭 counter bool

  👍
    💭 If divisible, add counter to sum
    📤 💯 ➕ 💾 💯       💭 sum = sum + counter
  🔚

  💭 Increment counter
  📤 🧮 🔢1 ➕ 💾 🧮     💭 counter = counter + 1

  💭 Test exit condition: counter > 999
  📤 🧮 🔢999 ⬆️
🔚

💭 Print the result
📤 💯 😀

Forth is fun because it is so easy to create a simple implementation of the language. It's also very very terse, which makes the emoji-nature of a project like this shine through. Here's the program above with emoji digits, fewer alphanumerics, and less whitespace:

💭 Project Euler Problem 1

📖❓ 📚 3️⃣🔀0️⃣🟰🔄5️⃣🔀0️⃣🟰⚡ 📕

📦💯
📦🧮

0️⃣ 💾💯
1️⃣ 💾🧮
🔁
  📤🧮📚
  ❓👍📤💯➕💾💯🔚
  📤🧮1️⃣➕💾🧮
  📤🧮🔢999⬆️
🔚

📤💯 😀

The project README has more detail on the language features if you're interested.

#emoji #forth #esolang

My post on using emoji in Crystal Language identifiers got some 🎉 attention. The obvious question was, how much further could I take a Crystal based solution? I played around with macros for a while to see how much syntax I could replace, but that path didn't go very far. Too much of the language, like block delimiters, showed through.

It turns out there is at least one programming language designed almost entirely around emoji—Emojicode. Emojicode is pretty cool and impressively complete, but because Emojicode is, at its core, a fairly traditional imperative language, it is difficult to keep the ASCII out. 🤔

I thought I could do better by modeling an emoji-based programming language on a stack-based language like Forth. 💡 Heavy use of recursion and the stack makes it easy to avoid naming things, which means ✨ less ASCII and more emoji ✨.

This ugly duckling defines a word (a function) that computes a factorial. The factorial word is the character ❗ (the syntax 📖❗ ... 📕 defines it as a new word). You can see that ❗ calls itself recursively, right?

💭 Factorial

📖❗📚2️⃣⬇️❓👍🗑️1️⃣👎📚1️⃣➖❗✖️🔚📕

🔢5❗😀   💭 120
🔢10❗😀  💭 3628800

You can use spaces and line breaks to make things more readable, but a lot of Forth code kind of looks like this to me so 🤷.

There's already a small number of primitive words and a standard library of additional words. I'll probably play around with the core a bit more and then publish it.

Tower of Hanoi 🏯 works, too!

#emoji #forth #esolang